Cloning of nisin resistance determinant and replication origin on 7.6-kilobase EcoRI fragment of pNP40 from Streptococcus lactis subsp. diacetylactis DRC3

The nisin resistance determinant and an origin of replication on pNP40, a plasmid of about 60 kilobases that is present in Streptococcus lactis subsp. diacetylactis DRC3, was cloned on a 7.6-kilobase EcoRI fragment. When self-ligated, this fragment existed as an independent replicon (pFM011) and contained a 2.6-kilobase EcoRI-XbaI fragment encoding nisin resistance.     

Cationic ferritin uptake by cultured anterior pituitary cells treated with the proteinase inhibitor, BOC-DPhe-Phe-Lys-H

Cultured cells from the anterior pituitary glands of adult rats were treated with the tripeptide aldehyde proteinase inhibitor, BOC-DPhe-Phe-Lys-H. The addition of this tripeptide aldehyde decreased the in vitro release of prolactin to 25% of the control value, while the release of growth hormone in the same cultures decreased to 33% of the control value. Prolactin immunostaining was stronger in semithin sections of proteinase-inhibitor-treated cultures than in control sections. After 2 h treatment with the inhibitor, prolactin- and growth hormone-containing secretory granules were numerous, and the number of crinophagic vacuoles had increased. In the presence of the inhibitor, the overall cytoarchitecture of parenchymal cells was well preserved, and the pathway of the uptake of cationic ferritin appeared to be unaffected.     

Major outer membrane protein in Salmonella typhimurium induced by maltose.

A maltose-induced major outer membrane protein (the 44K protein) is demonstrated in Salmonella typhimurium. This protein resembles the lambda receptor of Escherichia coli in its location, induction properties, apparent molecular weight, and association with the peptidoglycan layer of the cell wall. The 44K protein is missing in certain Salmonella Mal- mutants, which are also missing a protein analogous to the maltose-binding protein of E. coli. Thus, these mutants may be defective in the control of maltose genese in Salmonella. The proteins appear to be closely related, as indicated by cross-reaction of the Salmonella protein with the antiserum raised against the lambda receptor; however, they are not identical, since the peptide patterns obtained after limited proteolysis are completely different. Bacteriophage lambda does not use the 44K protein as a receptor.